I've had the same set of 55 F4 classics for about a year. After trying a new set of 60mm classics and going back to the 55s, I've noticed they have no bark at all. They still slide wonderfully, but they're almost completely silent.
Normal or nah? I need to get a new set either way, but it occurred to me that this is for sure the longest I've ever skated a set of wheels.